1. Field
Aspects of the present invention generally relate to a tandem type image forming apparatus that forms an image using a plurality of process cartridges each including a photosensitive member, a developing unit, and the like, and relates to an image forming apparatus such as an electrophotographic copying machine, a laser printer, and a facsimile apparatus.
2. Description of the Related Art
Conventionally, a process cartridge, which is formed by integrating an image bearing member such as a photosensitive member and a developing unit and is configured to be detachably mountable on an image forming apparatus main body, has been widely employed in electrophotographic image forming apparatuses such as color electrophotographic copying machines and color printers.
Japanese Patent Application Laid-Open No. 2010-91667 discusses a configuration in which a process cartridge is employed as an image forming unit, in an image forming apparatus according to the tandem type system (a system in which image forming units including photosensitive members, developing units, and the like for respective colors are arranged in series in a direction in which a transfer member travels, and a color image is formed by the image forming units).
Further, a configuration illustrated in FIGS. 14A and 14B is known as a conventional tandem type image forming apparatus. In FIGS. 14A and 14B, members having similar functions to the present exemplary embodiments that will be described below are identified by the same reference numerals. FIG. 14A is a main cross-sectional view illustrating an image forming apparatus with process cartridges 7 slid from the front of an apparatus main body 100A and mounted therein. FIG. 14B is a cross-sectional view illustrating the image forming apparatus with the process cartridges 7 moved to positions allowing image formation by raising guide rails 66 (moving members) from the state illustrated in FIG. 14A. In this manner, the process cartridges 7 are inserted into the guide rails 66 of the apparatus main body 100A with a certain space maintained between photosensitive members 1 and a belt 5 (FIG. 14A). After that, the photosensitive members 1 of the process cartridges 7 are brought into contact with the belt 5 serving as a transfer unit by raising the guide rails 66. Owing to this arrangement, the photosensitive members 1 are prevented from being rubbed against the belt 5 when the process cartridges 7 are being inserted in the apparatus main body 100A.
In the configuration illustrated in FIGS. 14A and 14B, detection units 8 for detecting remaining toner amounts in developing units 4 are held by holders 65. The holders 65 are fixed on a partition plate 80 in the apparatus main body 100A. The guide rails 66 are configured separately from the holders 65.
In the above-described conventional tandem type image forming apparatus, sufficient spaces are provided between the holders 65 and the moving members 66 so as to prevent the holders 65 holding the detection units 8 and the moving members 66 from contacting each other and interfering with each other when the process cartridges 7 are being moved to the positions allowing image formation by the moving members 66. This results in an increase in the distance between the adjacent process cartridges 7, leading to an increase in the size of the image forming apparatus main body 100A in the direction in which the process cartridges 7 are arranged.